{"operation":"document","citation":"14-0038","title":"Praxair Engineering Fellow — Hazardous Materials Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"2014-04-30","effective_on":null,"summary":"14-0038 response to Praxair Engineering Fellow concerning 180.207.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-14-0038.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-14-0038.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-14-0038","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2014/140038.pdf","body":"<<<PAGE 1>>>\n\nU.S. Department\nof Transportation\nPipeline and Hazardous\nMaterials Safety\nAdministration\n1200 New Jersey Avenue, SE\nWashington, D.C. 20590\nAPR 2 8 2014\nMr. Mahendra D. Rana, P.E., ASME Life Fellow,\nPraxair Engineering Fellow\nPraxair, Inc.\n175 East Park Drive\nTonawanda, NY 14151\nRef. No. 14-0038\nDear Mr. Rana:\nThis responds to your Febraury 27, 2014letter regarding the requalification testing\nrequirements for a seamless steel UN pressure receptacle (cylinder) under§ 180.207(d)(l)\nof the Hazardous Materials Regulations (HMR; 49 CPR Parts 171-180). Specifically, you\nask if the hydrostatic volumetric expansion test is an authorized testing method for\nrequalifying an \"H\" marked seamless steel UN cylinder with a tensile strength of< 950\nMPa.\nThe answer to your question is yes; Section 180.207(d)(l) requires that each seamless steel\nUN pressure receptacle is requalified in accordance with ISO 6406: Seamless Steel Gas\nCylinders-Periodic Inspection and Testing (see§ 171.7), but that UN cylinders with a\ntensile strength 2: 950 MPa must be requalified only by ultrasonic examination. ISO 6406\nrequires that each cylinder is submitted for either a pressure test or an ultrasonic\nexamination. The pressure test may be either the hydrostatic volumetric expansion or the\nhydraulic proof pressure test.\nISO 11114-1: Transportable gas cylinders, Compatibility of cylinder and valve\nmaterials with gas contents provides guidance in the selection and evaluation of\ncompatibility between UN seamless steel and the gas content. Specifically, ISO 11114-1\nstates that UN seamless steel cylinders with a tensile strength ::S 950 MPa, are compatible\nwith hydrogen, hydrogen mixtures and hydrogen bearing compounds including hydrides.\nSection 173.301 b(f) requires that cylinders compatable with hydrogen, hydrogen mixtures,\nand hydrogen bearing compounds bear an 'H' mark.\nIn a final rulemaking (HM-220E; 71 FR 33858, 33870; June 12, 2006) PHMSA stated that\nthose cylinders bearing an \"H\" mark may be pressure tested and those bearing no \"H\" mark\nmust be requalified by ultrasonic examination in accordance with ISO 6406 by an approved\nreq ualifi er.\nTherefore, \"H\" marked seamless steel UN cylinders may be pressure tested or subjected to\nan ultrasonic examination. PHMSA recognizes that as currently written §180.207(d)(l)\nconflicts with ISO 11114-1 with regard to the tensile strength values and the required\nrequalification method. It was PHMSA's intention that those cylinders bearing an \"H\"\n\n<<<PAGE 2>>>\n\nmark may be pressure tested and those not bearing the 'H' mark must be requalified by\nultrasonic examination in accordance with ISO 6406 by an approved requalifier. We\nintend to clarify the tensile strength values referenced in§ 180.207(d)(l) in a future\nrulemaking. A related letter of interpretation (Reference No. 13-0137) is attached for your\nreference.\nI hope this information is helpful. If you have further questions, please contact this office.\nSincerely,\nRobert Benedict\nChief, Standards Development Branch\nStandards and Rulemaking Division\n\n<<<PAGE 3>>>\n\nPraxair, Inc.\n175 East Park Drive\nTonawanda, NY, 14151\nPhone: 716-879-2000\n2/27/14\nTo: Director of Standards Division\nOffice of Hazardous Materials Technology & Research\nUS Department of Transportation\nSubject: Interpretation Request on Requalification UN cylinders\nThe present §180.207 (d) (1) on the requalification of UN pressure receptacles requires\nthat UN cylinders with a tensile strength greater than or equal to 950 MPa must be\nrequalified by ultrasonic examination in accordance with ISO 6406. UN cylinders designed and\nconstructed to ISO 9809-1 H mark have tensile strength less than or equal to 950 MPa.\nPresent wording in the above paragraph (d)(1) precludes the requalification of the H marked\ncylinders by hydrostatic test with tensile strength equal to 950 MPa. We are requesting the\nfollowing interpretation.\nQuestion: For H marked UN cylinders, can hydrostatic test be used in lieu of the specified\nultrasonic test in §180.207 (d) (1).\nAnswer: Yes, UN cylinders with H mark may be requlified by hydrostatic test.\nVery truly yours,\nMahendra D. Rana, P.E., ASME Life Fellow,\nPraxair Engineering Fellow\nPraxair, Inc.\n1 7 5 East Park Drive\nPhone & Fax No: (716) 879-2408/2907\nE-mail: Mahendra_ Rana@praxair.com","truncated":false,"body_characters":4306}